To change the size of your desktop mirrored on your TV, click in the menu bar. Then select Mirror Built-in Display to match the size of your desktop or Mirror Apple TV to match the size of your TV.
AirPlay also lets you use your TV as a separate display for your Mac. Just click in the menu bar, then select Use As Separate Display.
To stop mirroring or using your TV as a separate display, click in the menu bar, then choose Turn AirPlay Off. Or press the Menu button on your Apple TV remote.
Adapters vary depending on your computer’s video inputs.
After checking this box, wait several seconds. Once the displays are mirrored, you should see the same image on both your projector and computer.
To stop streaming video, click in the video playback controls, then choose Turn Off AirPlay.
Use Screen Mirroring to see the entire screen of your iOS device on your Apple TV.
Your TV uses your iOS device's screen orientation and aspect ratio. To fill your TV screen with the mirrored iOS device screen, change your TV's aspect ratio or zoom settings.
To stop mirroring your iOS device, open Control Center, tap Screen Mirroring, then tap Stop Mirroring. Or press the Menu button on your Apple TV remote.
To stop streaming, tap in the app that you're streaming from, then tap your iPhone, iPad, or iPod touch from the list.